Metallurgy of steel.



' sary) that the solution should be made with WILLIAM SPEIRS SIMPSON ANDHOWARD OVIATT, OF LONDON, ENGLAND.

METALLURGY OF STEEL.

Specification of Letters Patent.

Patented April 13, 1909.

Application filed November 16, 1908. Serial No. 462,906.

To allwh'om it may concern:

[Be it known that we, WILLIAM SPEIRs SIMPSON, a subject of the King ofGreat Britain, and HOWARD OVIATT, a citizen of the UnitedStates ofAmerica, both residing at London, England, have invented certain new anduseful Improvements in Connection with the Metallurgy of Steel, of whichthe followingris a specification.

his invention has for its object the red uction of iron oxids to metaland the production of steel and various alloys thereof direct from ironores especially from the ores in which iron occurs as an oxid; such forinstance as hematite and magnetite or their compounds.

The method or process is adaptable to any form of iron oxid capable ofbeing crushed or ground for mixing purposes as hereinafter set forth,but is peculiarly adapted to the treatment of concentrates or of oresalready existing as natural products, such as magnetic iron sand or ofpartially decomposedsesquioxid of iron.

In carrying out the purposes of the invention we thoroughly mix anyconvenient quantity ofsuitable ore or mixtures of ores which if notalready in a comparatively fine state of division has been so prepared,with an aqueous solution sul'licient in quantity to form astiff pastesuitable for being placed in or packed into a receptacle prepared forthe purpose and made ready as a furnace or crucible charge for beingsubjected to heat. This solution is composed of water and a carbo-hdrate such as sugar or other saccharine su stance or compound, or suchas starch, flour or other starchy substance or compound. It is advisable(but not neceshot water in order to more perfectly dissolve thecarbo-hydrate employed. The quantity of such carbo-hydrate required toeffect the desired result in respect to the reduction of the metallicoxids under treatment and the production of steel therefrom, variesaccordmg to the character of the oarbo-hydrate so employed and accordingtov the character of theoreor mixture of ores to be reduced andconverted into steel. Thus if magnetic iron sand (which contains but asmall proportion of angue) represents the ore to be reduced andconverted into steel and if ordinary brown sugar represents thecarbo-hydrate to be employed, the quantity of sugar should beapproximately equal to four or five per cent.

of the weight of the ore to be treated. The employment of an excess ofsuch carbo-hydrate is not detrimental to the accomplishment of thedesired result and in some cases if an excess of sugar is employed thewater may be omitted. In addition to the carbohydrate dissolved or mixedwith water in the manner described there is also thoroughly mixed withthe ore to be treated either a small quantity of finely powderedmanganese dioxid equal to from 3% (or less) to 6% (and upward) of theweight of the iron ore (according to the character of the ore and theresult required) or instead thereof an equivalent quantity of finelyground manganese ore containing the requisite proportion of manganesedioxid.

In some cases, when the iron ore contains a considerable percentage ofsilica, alumina, lime or other gangue, the carbohydrate employed may,with advantage, be considerably increased. In almost every case unlessalready present in the crude ore there should also be intimately andthoroughly mixed with the ore charge, sufficient lime, alumina, silica,or other convenient fluxing material which has been crushed or groundfor the purpose, in suitable proportions to form, during the process ofheating and reduction, a liquid slag, which may be either acid or basicas may be best suited to the ore under treatment.

In case it is desired to produce steel con taining any fixed percentageof combined carbon it is necessary to add to the ore charge beforesubjecting the same to heat, a suitable quantity of finely groundgraphite or other suitable form of carbon which should be carefullymixed with the iron ore or mixture of ores before the carbo-hydrate andthe water are mixed therewith. The quantity of graphite to be used forthis purpose will vary with the different qualities and characteristicsof the iron ore under treatment, but the general statement may be madethat 2% of graphite added to the charge will result in a high carbonsteel containing about 67% of combined carbon and that 4% of graphitendll result in a steel containing 1.95% of combined carbon. In fact bythis simple method any desirable percentage of combined carbon may (atthe will of the operator) be introduced into the steel during theprocess of reducing the ore from which the same is made. And such steelwill contain the manner hereinbefore described may be placed in anysuitable receptacle or vessel (with or without a cover) and subjected toheat in any convenient manner or in any convenient form of furnacewherein it is practicable to create and maintain a heat equal to orsomewhat higher than the melting point of steel. Or the prepared orecharge may be packed into or suitably placed within the hearth of afurnace such a Siemens open hearth regenerative furnace fired byproducer gas. The hearth of such furnace should be provided with asuitable lining composed of such material as ganister, magnesite, or arefractory carbonaceous compound. VJ hen subjected to a heat varyingfrom 2600 F. to 3000 E, for a period of time varying from two hours tofive hours (and upward) according to the magnitude of the charge, thereis produced mild steel (low in carbon) or steel (high in carbon) equalto the best crucible steel, of great purity and uniformity of characterand of the highest quality. The percentage of combined carbon containedtherein being entirely at the command of the operator.

If it is required to produce steel containing various other metalsdesirable as alloys, a suitable mixture of ores containing the metalsrequired, in the desired proportions, may be brought together in the orecharge and the requisite steel alloy will in most cases result from theone operation.

In some cases and with some ores it is de sirable to augment the actionof the carbohydrates mentioned (sugar, starch etc.) by associating withthe ore and fluxes a small quantity of ground coke, coal, charcoal orther form of carbon not exceeding 15 or 20 per cent. of the weight ofthe ore; which may 11' may not be intimately mixed therewith; but mustbe of such character and be employed under such conditions as to assistin the reduction of the metallic oxids rather than to carburize themetal. And in some cases where a considerable proportion of lime is tobe employed for fluxing purposes the same may be introduced in the formof ground calcium carbonate mixed with about 12% of its own weight offinely ground charcoal or other carbon; it may be placed in the bottomof the receptacle or furnace hearth before the ore charge is placedtherein; which mixture, when heated, yields active reducing gases.

Vv hat we do claim as our invention, and desire to secure by LettersPatent is 1. A process of manufacturing steel directly from ore whichinvolves reducing the ore by means of a carbo-hydrate and effectingcarburization of the metal by means of another form of carbon at thesame operation.

2. A process of producing steel directly from 'ore which involves theintimate association of a carburizing carbon and a reducingcarbo-hydrate w th the ore, and then heating the ore charge thusprepared to effect its reduction and the carburization of the metal.

8. A process of manufacturing steel directly from ore which involves theintimate association of ore in a fine state of division, graphite and areducing carbo-hydrate in combmaof division and adding thereto areducing carbonaceous substance containing water, and then heating theore charge thus prepared to effect its reduction and the carburizationof the metal.

5. A process of manufacturing steelwhich consists in preparing an orecharge containing a carburizing carbon, a reducing carbohydrate and asuitable percentage of manganese di oxid and a fluxing material suitableto produce a liquid slag, all in a fine state of division and intimatelymixed, and then heating the ore charge thus prepared to reduce it and topurify and carburize the metal.

6. A process of manufacturing steel directly from iron ores whichconsists in preparing an ore charge containing the ore in a fine stateof division, a carbohydrate combined with water, and manganese dioxid,all intimately mixed, and heating the ore charge thus prepared to effectits reduction and conversion of the metal into steel.

7 An improvement in the art of manufacturing steel directly from ironores which consists in intimately associating a carburizing carbon withthe ore in a fine state of division and adding thereto a carbo-hydrate,and then heating the ore charge thus prepared.

8. The herein described improvement in the process of manufacturingsteel which consists in mixing a carburizing carbon with iron ore in afine state of division, adding thereto a carbo-hydrate and an aqueousliquid, and then heating the ore charge thus prepared.

9. A process of manufacturing steel directly from iron ores whichinvolves the mixing of finely ground graphite with the ore in a finestate of division, adding'to said mixture a carbo-hydrate dissolved inwater, and then heating the ore charge thus prepared.

10. The herein described improvement in carbon both in a fine state ofdivision and the art of reducing ores which consists in our hands inpresence of two subscribing assoclatm wlth an ore charge contamlng awltnesses.

carbo-hy rate and man anese dioxid a a a WILLIAM SPEIRS SIMPSON. mlxtureof calclum carbonate and a su1tab1e HOWARD OVIATT.

intimately mixed, which under heat are Witnesses:

effective to yield reducing gases. RICHARD COVE GARDNER,

In testimony whereof we have hereunto set LYNWoon T. GARDNER.

